Multi-channel fluid elements



Sept. 12, 1967 R. w. WARREN ETAL 3,340,884

MULTI-CHANNEL FLUD ELEMENTS Original Filed Aug. '7. 1963 wwm. Mg

ATTORN EY United States Patent @ffice 3,340,884 Patented Sept. 12, 1967 3,340,884 MULTI-CHANNEL FLUID ELEMENTS Raymond W. Warren, McLean, Va., and Ronald. E. Bowles, Silver Spring, Md., assignors to the United States of America as represented by the Secretary of the Army (lriginal application Aug. 7, 1963, Ser. No. 300,709, now Patent No. 3,238,958. Divided and this application Oct. 29, 1965, Ser. No. 516,814

3 Claims. (Cl. 137-815) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment to us of any royalty thereon.

This application is a division of application Ser. No. 300,709, filed Aug. 7, 1963, now Patent No. 3,238,958.

This invention relates to fluid amplifiers and, more particularly, to fluid amplifiers with multiple dividers.

In the development of fluid amplification, it is necessary that fluid amplifiers produce their lfunctions while being matchable to other amplifiers or devices without loss of operating pressures and without overloading any of the components. This is accomplished in this invention Iby maintaining the interaction chamber of these lockon type amplifiers at ambient conditions. In order to introduce ambient conditions into the interaction chambers, a breather channel is provided, in some examples, between a pair of dividers extending from the interaction chamber to the ambient condition. The other sides of the dividers form walls for the receivers. Also, variations of multisplitter divider amplifier structure produced an organ pipe type amplifier wherein the control channels depend upon pipe organ characteristics for their operation.

It is, therefore, an object of this invention to provide a fluid amplifier which is capable of being impedance matched to other fluid elements.

Another object of this invention is to provide a fluid amplifier in which the interaction chamber is maintained at ambient condition.

A still further object of this invention is to provide an organ pipe fluid oscillator with either open pipe controls or closed pipe controls.

Another object of this invention is to prevent reflection of compression, rarifaction and sonic waves in a fluid amplifier.

The specific nature of the invention, as well as other objects, uses and advantages thereof, will clearly appear from the following description and from the accompanying drawing, in which:

FIG. 1 is a plan view of a first embodiment of a bistable fluid amplifier.

FIG. 2 is a plan view of a closed end organ pipe fluid oscillator.

FIG. 3 is a plan view of an open end organ pipe fluid oscillator.

Briefly, the elements of this invention include structure incorporating the principle of keeping the interaction chamber of fluid amplifiers at the ambient pressure condition by access channels connecting the interaction chambers and the ambient region. This principle Ais adaptable to several embodiments of fluid amplifiers and can be utilized to assure impedance matches of connected elements. The structural modification which incorporates the above stated principle led to the organ pipe oscillators in which the opening to the ambient of the control organ lamina 11 is a cover plate through which the various inputs to the fluid amplifier are applied. The center layer 12 is machined, drilled, or etched or otherwise grooved to present the openings therein which enable a primary fluid stream to be controlled by secondary fluid streams. The bottom lamina 13 has no openings therein so as to seal the unit. The fluid streams are confined between the top and bottom layers 11 and 13 so as to flow through passages provided in center layer 12.

A fluid power source, not shown, is connected to the power nozzle 14 so as to ad-mit a fluid power stream throughpower opening 15. A power stream is introduced into interaction chamber 16 through power nozzle 14. Chamber 16 is bounded by right sidewall 17 and left sidewall 18 and is in communication with right receiver 21, left receiver 22 and a central channel 23. Central channel 23 is separated from right receiver 21 by a first divider 24. Central channel 23 is separated from left receiver 22 `by a second divider 25. Interaction chamber 16 is bounded at its lower end `by the structure limiting the power nozzle 14 to a small opening, the right control nozzle 26 and the left control nozzle 27. Left control nozzle 26 is fed a control signal through opening 28 in top layer 11 of the laminated package. Left control nozzle 27 is fed a control signal through -opening 29 lin the top layer 11. It is to be noted that the sidewalls 17 and 18 are wider at their extremities near the power jet nozzle 14 than the width of the said power nozzle 14. Further, sidewalls 17 and 18 are divergent downstream of the power nozzle 14. The three downstream passageways, receiver 21, receiver 22, and central channel 23 are either connected to atmosphere or are closed in a selected pattern or are connected to a selected load as will be discussed later in this specification. i

FIG. 2 shows a second embodiment of the multi-divider fluid element of this invention. It is seen that the fluid amplifier shown in FIG. 2 resembles the fluid amplifier in FIG. l, in that the control nozzles have been removed and the original receivers have been rotated such that the original sidewalls 17 and 18 are now aligned on the same line and that the original central passage 23 has been modified to be two receivers. The device of FIG. 2 would operate with a single output receiver. The multi-divider fluid element 30, shown in FIG. 2, has a laminated construction as in FIG. 1 and other gures of this disclosure. A fluid power stream from a power source, not shown, is introduced through opening 31 in the top layer to a vpower nozzle 32 in the center layer. The power stream issuing from power nozzle 32 enters an interaction chamber 33. A right control channel 34 and a left control channel 35 are axially aligned and are perpendicular to the flow of the power stream as it egresses from power nozzle 32. The relationship of the sizes of the openings into the interaction chamber 32 is not critical. However, a very good relationship of sizes would -be that the width of the control channels and the receivers be approximately twice the width of the power nozzle 32. With the sidewalls of the receivers 37 and 38 being divergent in configuration as provided by the divergent divider 36, the narrowest width of interaction chamber 33 that is parallel to the axis of the control channel 34 and 35 is approximately twice the width of the issuing end of control nozzle 32.

The fluid element illustrated in FIG. 3 differs from the modification shown in FIG. 2 only in the closing of the control channels to provide a right closed tube control channel 41 and a left closed tube control channel 32 in the fluid element 40. Otherwise, the structure of fluid element 40 shown in FIG. 3 is the same as the structure of fluid element 30 shown in FIG. 2.

The species of FIG. 2 can be modified by the addition of valves to vary the amount that the control channels 34 and 35 are opened and closed. This provides all of the features of both species as shown in FIGS. 2 and 3 and all of the intermediate configurations. Further, the species of FIGS. 2 and .3 can be modified with any adjustable means that can alter the width-length relationship of the control channels. This could be accomplished by adjustable sleeves, or pistons movable -channel walls and the like.

A variety of eifects can be achieved in fluid amplication devices by the division of a space with dividers. Oscillation can be produced or eliminated, units can be combined with repeatable pressure patterns, control flows can be combined or partitioned.

In the operation of the multi-divider element as shown in FIG. 1, the normal activity of the power jet is to cling to the right or the left boundary wall, 17 or 18, and exit through the right or left outlets 21 or 22, respectively. If the power jet is on the right, that is attached to wall 17 and leaving through right outlet 21, the power jet may be ipped to the left by allowing uid to enter the right control nozzle 26 or by withdrawing lluid from the left control nozzle 27. The power jet stream is stable in its new position when the controls are removed. If control ow is introduced in both controls in suflicient volume to equal the entrainment characteristic of the power jet stream, the power jet will be detached from the boundary walls and ow through the center passage. Unless the two dividers -are very close to the power jet orifice, and the boundary walls are spaced well back from the power jet stream, the power jet stream will attach to one of the boundary walls as soon as the control streams are removed. If the right and left outlet, 21 and 22, are partially or fully blocked, the power jet stream will oscillate between the right and the left outlets producing a pulse flow in the center outlet 23. This action is caused by the power stream evacuating fluid between itself and a boundary wall. The power stream moves toward the wall and raises the pressure in the side outlets. For purposes of illustration, assume that the side outlet is the right control nozzle 26. This raises the pressure in the blocked right passage 21. The reverse wave of higher pressure forces the stream toward the left, that is toward lock-on wall 18. As the power stream moves toward the left, a pulse of ow exits through the center outlets and the stream continues its movement toward the left passage. The stream being closer to the left wall entrains fluid between the stream and the wall 18, and moves still further toward the left boundary wall raising the pressure in the blocked left passage 22. The wave of higher pressure back down the left passage 22 now forces the stream toward the right wall 17 sending another pulse of ilow through the center passage 23 as the power stream passes the entrance thereto. The oscillation can be prevented by allowing suicient ow to exit through the right and left passages 21 and 22 or by widening the center outlet 23 so that it is considerably wider than the power jet stream.

The oscillation is enhanced by having the lengths of the partially or fully blocked right and left passages 21 and 22 equal. The standing waves in the equal lengths reinforce each `other in the proper phase relation to produce oscillation.

When lthe center channel 23 is lclosed, such closure is equivalent to a cusp-type divider as disclosed in the copending application Ser. No. 222,748 tiled Sept. 10, '1962, by Raymond W. Warren, one of the instant inventors, Ralph G. Barclay and John G. Moorhead Afor Feedback Divider for Fluid Amplier. The closing of center channel 23 causes stabilization in the manner of the cusp-type divider discussed in the said co-pending application. In this circumstance, the multi-divider element shown in FIG. 1 can operate as an amplifier. When the three outlet passages 21, 22 and 23 are all open, this element is a stable amplier. When channels 21 and 22 are suiciently blocked or closed entirely and center channel 23 is open, the uid element will perfonm as an Oscillator.

The above description of operation of the uid element in FIG. l as an oscillator applies when the relationship of size of the openings into the interaction chamber are substantially as shown in FIG. l. That is, with the width of the power nozzle being labeled W, the width of the two central nozzles are also W and the three exit channels are 2W, or the center channel 23 can Ibe less than 2W wide. It is further assumed that the points of the dividers 24 and 25 are at least 5 nozzle widths downstream. Closer than 5W, there is insuicient force from the sidewalls to prevent the power stream from egressing through the center channel 23. Closer than 5W, the reduced entrainment over the shorter distance does not provide sufficient lpressure differential acting on lthe shorter distance to effect an appreciable deection of the power jet so the power stream egresses through center channel 23, This, in eiect, results in the amplifier being a proportional amplifier when the dividers are close to the power nozzle. A proportional amplifier is a fluid amplier in which there is no wall lockonto give stability to the power stream. The power stream is directed by its nozzle toward the receivers and is redi- .rected to a specific receiver or group of receivers by control streams, the actual path of the power stream being determined by the momentum of the fluid ow of the power stream Combined with the control streams.

Movement of the dividers toward each other narrowing the center channel 23 and opening the side channels 21 and 22 tends to make the unit oscillate when the outside channels are loaded. Loading is dened as being the progressive closing of an output channel such as by a piston or a valve. Oscillation of the power stream 4results from the severe Ibending of the power stream when the stream iirst locks on to a wall of a receiver which, when loaded, will not conduct the power stream outward and the power stream must seek a path outward through the central passage 23. With the divider considerably distant from the sidewall, the power stream must make a bend of such magnitude that it fails to lock on to the wall of the central channel that is on the divider separating the loaded receiver from the central channel. With the lock-on failure, the stream continues across the central channel toward the other wall thereof and bounces back toward the rst men. tioned `wall in said channel. This stream activity results in the stream oscillating at a stable frequency after the beginning instabilities dampen out, when both of the receivers are loaded.

Movement of the dividers away from each other opening the central channel 23 and narrowing the outside channels 21 and 22 reduces or tends to eliminate the oscillation of the power stream as the outside channels are loaded. With the central channel suiliciently wide and the outside channels correspondingly narrow the stream from the power nozzle first locks on to an outside wall 17 or 18, travels around the point of the divider 24 or 25 whichever is closest to the locked-on wall 17 or 18 proceeds to lock on to the side of such divider and go on out the central channel 23 without oscillation. Another way of preventing oscillation is to introduce porous plugs into the output channels 21 and 22 whereby the power stream will lock on to the conventional lock-on walls 17 or 18` and then bend to go out through the center channel and lock on to a divider wall without oscillation.

In the example when the channels are one half the width of the power nozzle and the central channel is twice the width of the power nozzle, the blocking of outlet channels with the control channels remaining open, the power jet will be stable in the central channel 23. If, additionally, a control flow is introduced into one of the control channels 26 or 27 and the other is either open or closed, the power jet will oscillate between the two outlet channels 21 and 22.

In the operation of the oscillator of FIG. l, a comparatively high gain is required for the starting of the oscillation. This high gain can be introduced by restricting the Qlllle. Qllmll or by connecting a, load thereto- In the operation of the open end organ pipe oscillator shown in FIG. 2, the power stream issuing from nozzle 32 will lock on to either of the sidewalls of chamber 33 to select outlet channel 37 or outlet channel 38. The control nozzles 26 and 27 of FIG. 1 have been replaced by control ports 34 and 35 in FIG. 2. These ports are relatively long, narrow passages. The uid in control ports 34 and 35 is set into vibration in the tubes 34 and 35 by the blowing past the openings of the tubes by the power stream. The anti-node occurs at the open end of the tube near the power nozzle so that the displacement of uid is a maximum at this point. It is this action of displacement of uid at the inner end of the control tube that causes the power stream to oscillate. When the tubes 34 and 35 are of equal length, the oscillation is reinforced.

As in pipe organ pipes, the fundamental frequency of the control pipe of the oscillator in FIG. 2 is equal to the velocity of sound divided by the length of the wave traveling through such pipe at the rvelocity of sound. Since a closed pipe is inherently one half of the wave length of the fundamental frequency, the fundamental frequency is equal to the velocity of sound divided by two times the pipe length. The rst overtone is equal to the velocity of sound divided by the pipe length. The second overtone is equal to three times the velocity of sound divided by two times the pipe length. The other overtones follow as in an organ pipe. These overtones are generated by overblowing in the oscillator of this invention as in a pipe organ.

In the operation of the open pipe oscillator shown in FIG. 3, the relationship of the sizes of the openings intov the interaction chamber 32 is such that all of the nozzles are at least as large as the power nozzle. It has been found that when the other nozzles are twice the power nozzle opening, the oscillator operates very well. It is possible to switch the mode of operation under loading to double or half the frequency. Through a prescribed pressure range or flow range, the organ pipe type of oscillators are very stable. In both the open and the closed organ pipe type oscillators, the length of the pipe determines the frequency of oscillation, since the time for the control pulse to travel through the pipe is a function of the distance traveled. The width of the outlets of the control pipes can be changed by Valves, for example, to vary the effective length of the pipes and, correspondingly, the frequency from the velocity of sound divided by twice the pipe length to the velocity of sound divided by four times the pipe length, that is, from an open pipe to a closed piped. Further, the length of the pipes can be changed to effect frequency changes as by pistons, for example.

The operation of the closed pipe oscillator shown in FIG. 3 is the same as the operation of the open pipe oscillator shown in FIG. 2 with the exception of the difference of fundamental frequencies as set forth above. The fundamental frequency for the closed pipe oscillator is the velocity of sound divided by four times the length of the pipe. The first overtone is three times the Velocity of sound divided by four times the length of the pipe while the second overtone is tive times the velocity of sound divided by four times the length of the pipe, and so on.

So it is seen that we have provided fluid amplifiers in which impedance matching to other uid elements is accomplished, and in which reection of compression, rarifaction and sonic waves is accomplished.

It will be apparent that the embodiments shown are only exemplary and that various modications can be made in construction and arrangement within the scope of the invention as defined in the appended claims.

We claim as our invention:

1. In an organ pipe oscillator:

(a) a fluid power nozzle having a width W,

(b)l a power iuid source connected to said power noz- (c) an interaction chamber,

(d) said power nozzle positioned to direct power Huid into said interaction chamber,

(e) a pair of oppositely disposed axially aligned control tubes, each of said control tubes having two ends and being of a constant cross-sectional width 2W,

(f) one end of each of said control tubes opening into said interaction chamber, and

(g) a pair of receiving conduits, each of width 2W,

communicating with said interaction chamber.

2. A device according to claim 1 wherein the second end of each of said control tubes is open to ambient.

3. A device according to claim 1 wherein said second end of each of said control tubes is closed to ambient.

References Cited UNITED STATES PATENTS 3,016,066 1/1962 Warren 137-81.5 3,098,504 7/1963 Joesting 137-815 3,122,165 2/1964 Horton 137-815 3,144,037 8/1964 Cargill et al 137-815 3,148,691 9/ 1964 Greenblott 137-815 3,158,166 11/1964 Warren 137-815 3,185,166 5/1965 Horton et al. 137-815 3,192,938 7/1965 Bauer 137-815 3,204,652 9/1965 Bauer 137-815 M. CARY NELSON, Primary Examiner.

S. SCOTT, Assistant Examiner. 

1. IN AN ORGAN PIPE OSCILLATOR: (A) A FLUID POWER NOZZLE HAVING A WIDTH W, (B) A POWER FLUID SOURCE CONNECTED TO SAID POWER NOZZLE, (C) AN INTERACTION CHAMBER8 (D) SAID POWER NOZZLE POSITIONED TO DIRECT POWER FLUID INTO SAID INTERACTION CHAMBER, (E) A PAIR OF OPPOSITELY DISPOSED AXIALLY ALIGNED CONTROL TUBES, EACH OF SAID CONTROL TUBES HAVING TWO ENDS, AND BEING OF CONSTANT CROSS-SECTIONAL WIDTH 2W, (F) ONE END OF EACH OF SAID CONTROL TUBES OPENING INTO SAID INTERACTION CHAMBER, AND (G) A PAIR OR RECEIVING CONDUITS, EACH OF WIDTH 2W, COMMUNICATING WITH SAID INTERACTION CHAMBER. 